dramatic clashes in turkey, where police are taking on anti-government protesters in the heart of that country's capital. Alex marquardt is there. Turkey is a key u.S. Ally that borders syria, iraq and iran. Reporter: That's right, george. This square behind me has been ground zero for the protests. And overnight, it resembled a war zone, with riot police moving in, firing tear gas and water canons against the protesters. Setting the stage for what could be another violent day. Rocks, fireworks and tear gas flying through the air, as protesters clashed with police overnight, in the worst violence since the protests started. They shoot right into the crowd. And people were basically running. And people were afraid to be run over. Reporter: In protests that have spread across the country, three people have been killed and thousands wounded. Globally, turkey is the sixth-most visited country by tourists. Over 500,000 americans visit every year. That could be in jeopardy with these biggest protests in decades. Shaking the leadership of this man, prime minister recep tayyip erdogan. Here, they're say he's increasingly authoritarian and imposing his will of islam. He wants to control anything. He doesn't want anything against him. Reporter: The prime minister says he has the support of the majority of the turkish population. And he won't tolerate the protests. It's hard to see how these protests end peacefully.

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